多天线蜂窝系统中的下行协作波束成型传输

多天线蜂窝系统中的下行协作波束成型传输

内容简介：在使用波束成型传输数据的蜂窝系统中,为提高下行链路的频谱效率,需要多小区多用户之间协作地产生波束.以多小区多用户下行链路的数学模型为基础,计算了各用户波束发送滤波器、接收滤波器、发送功率三类变量的梯度,使这些变量不断沿梯度方向调整并投影至可行空间,从而提出了一种基于梯度投影的多小区多用户下行协作波束成型传输方案,并分析了该方案需要在相邻小区基站间交互的信息.仿真结果表明,该方案在典型场景与参数配置下可达到约5 bit/(s·Hz·cell)的平均频谱效率性能.因此,多小区多用户之间的有效协作有助于提高蜂窝系统频谱效率性能.

Abstract：In downlink cellular systems using beams, the multiple users in multiple cells should cooperate to generate beams to improve the spectrum efficiency. A mathematical model for the multi-cell multi-user downlink transmission is established, and the gradients of the variables including beamforming filters, receiving filters and transmitting power are calculated. Then, a gradient-project-based cooperative beamforming scheme is proposed in which each user iteratively adjusts beamforming variables in the direction of the gradients and projects onto feasible spaces. The information exchange protocol needed to support the scheme is also described. Simulation results show that the proposed scheme can achieve an average spectral efficiency of about 5 bit/(s·Hz·cell). The results show that cooperative beamforming can improve the spectrum efficiency of the cellular systems.

作者：张源,

关键词：蜂窝系统, 多输入多输出, 协作预编码, 频谱效率,